Flow Velocimetries Based on Laser Induced Fluorescence Photobleaching


Reference #: 01351

The University of South Carolina is offering licensing opportunities for Flow Velocimetry based on laser induced fluorescence photobleaching.



Transport phenomena (fluid mechanics, heat transfer, mass transfer) play a key role for the performance of micro/nanofluidic devices. To understand the transport phenomena, one needs to measure the flow velocity profile first. Most velocimeters in micro/nanofluidics rely on flow tracer particles, such as micro Particle Image Velocimetry (μPIV). Particle Image Velocimetry is an optical method of visualizing the instantaneous velocity measurements are other properties in fluids. The fluid is seeded with tracer particles which are assumed to follow the flow dynamics of the observed fluid.


Invention Description:

Proposed is a novel nanoscopic velocimeter that is based on two-photon excitation and neutral molecular dye as flow tracer to avoid issues in conventional velocimeter using particles as a tracer, significantly increase spatial and temporal resolution simultaneously and penetrate deep in a medium like blood. The method could enhance fundamental researches to improve the performance of micro/nanofluidics devices. This invention measures fluid flow velocity with high spatial and temporal resolution. The method includes a calibration free method which uses a time of flight (TF) and laser induced fluorescence photobleaching anemometer (LIFPA), i.e. TF-LIFPA, with two focus light beams to measure the flow velocity. We can also use this method as a calibration method for LIFPA, which can achieve simultaneously high spatial and temporal resolution. To enable deep penetration for fluids with strong absorption of light, such as blood, we will use multiphoton (e.g. two photon) absorption LIFPA. If we combine with two-photon and stimulated emission depletion (STED), we can achieve nanoscopic spatial resolution. Therefore, combining them together, we can achieve a new velocimetry system with high spatial and temporal resolution and high penetration.


Potential Applications:

Analysis of transport phenomena in fluids including blood, determining flow rates using LIFPA to analyze blood flow at a nanoscopic resolution. The high spatial and temporal resolution helps provide a breadth of data. This invention can be applied in fluid analysis of any type, but has specific use in thicker mediums such as blood.


Advantages and Benefits:

Better temporal and spatial resolution than what are available in the market currently with laser-induced fluorescence photobleaching. Current methods of velocimetry primarily rely on particles as tracers, such as micro Particle Image Velocimetry (µPIV). These such methods are limited in accuracy and temporal and spatial (100 µm) resolution, however, and cannot measure the velocity profile of a fluid in a tube on such small scale as necessary in vivo. As a result of these limitations, we are developing a novel molecular tracer-based method to measure flow velocity profiles in microcapillaries and nanocapillaries in vitro called Two Photon-Laser Induced Fluorescence Photobleaching Anemometry (TP-LIFPA) which can achieve resolution of 100 nm.

Patent Information:
Title App Type Country Serial No. Patent No. File Date Issued Date Expire Date Patent Status
Measurement of Fluid Flow Velocity with High Spatial and Temporal Resolution Utility United States 16/558,410 11,674,834 9/3/2019 6/13/2023   Issued
For Information, Contact:
Technology Commercialization
University of South Carolina
Guiren Wang
Audrey Wang
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